The invention relates to a disc reproducing apparatus which can reproduce a CD-I disc on which image data and the like in addition to audio data are recorded.
2. Description of the Prior Art
There has been proposed a CD-I (CD Interactive) system in which image data (natural image, animation, computer graphics, etc.), text data, program data, and the like in addition to audio data are recorded onto a CD (Compact Disc) and which can execute the operation in an interactive manner. Since such a CD-I system has a reproducing function of characters, images, audio data, computer data, etc., it can be used in AV industrial apparatuses mainly for the purpose of audio and video fields, electronic publishing which mainly handles characters, data base services mainly comprising information files, education and amusement which are mainly executed by interactive responses, and the like. Thus, the CD-I system is expected as a medium of a new format.
In the CD-I system, various data specifications are predetermined so that it can widely be spread as a home-use system while keeping a compatibility. That is, in the CD-I system, a CPU of the 68000 type (microprocessor of 16 bits developed by Motorola Inc.) is used and an operating system which is fundamentally based on widespread OS9 is used as a real-time operating system which handles various kinds of files. Two trigger buttons and an X-Y device are used as an input device. Two audio and video systems are prepared as an output system. The CD-I player is constructed so that it can reproduce ordinary compact disc for a music.
As mentioned above, in the CD-I system, it has been predetermined to use two trigger buttons and an X-Y device as an input device and all of the operations can be executed by using the two trigger buttons and the X-Y device at a minimum. In the input device having such limited keys, however, there is a limitation in improvement of the operability. Particularly, in the case of executing the audio reproduction by the CD-I system, it is demanded that the operations can be performed in conformity with those of the conventional compact disc player for musics.